1. Field of the Invention
Embodiments describe herein generally include an apparatus for plasma cleaning and a method for plasma cleaning.
2. Description of the Related Art
Physical vapor deposition (PVD) is a method of depositing a material onto a substrate. A PVD chamber may have a sputtering target disposed within a processing chamber and situated opposite a substrate. A sputtering gas, such as argon, is introduced into the chamber. The sputtering target, when metallic, may be electrically biased with a DC current to ignite the argon gas into a plasma. The substrate, on the other hand, may be grounded to act as an anode relative to the electrically biased sputtering target. Atoms from the sputtering target may eject or sputter from the sputtering target and deposit a metal film on the substrate.
While the atoms from the sputtering target may deposit onto the substrate, the atoms may also deposit on exposed surfaces within the chamber. For example, material may be deposited on the chamber walls and other chamber components including deposition rings. Over time, the material deposited onto the chamber walls and components may build up to a sufficient thickness that the chamber needs to be cleaned.
Additionally, dielectric material and other organic residues may be deposited onto the substrate in other chambers. Whenever the chamber is opened to permit a substrate to enter and/or exit the chamber, dielectric material may enter into the chamber. The dielectric material may be present in other chambers and flow into the chamber where it may condense on the chamber surfaces, including the susceptor. If the susceptor is an electrostatic chuck and sufficient dielectric material builds up on the susceptor, the electrostatic charge of the susceptor, when biased, may be shielded by the dielectric material and prevent the substrate from being attracted to the susceptor. If there is sufficient dielectric material built up on the susceptor, the substrate may pop off of the susceptor due to insufficient electrostatic charge, possibly resulting in damage to the substrate and/or chamber components.
Plasma cleaning processes have been developed for removing dielectric material and other organic residues from chamber components such as the susceptor. However, when performing these plasma cleaning processes, the metallic material deposited on the chamber components including the deposition ring may be resputtered throughout the chamber including onto the surface of the susceptor thus rendering the susceptor unusable. Currently, due to the danger of resputtering metallic material, plasma cleaning processes are typically performed after venting the processing chamber and inserting a new deposition ring into the chamber. After metallic material is deposited on the deposition ring, the current plasma cleaning processes are generally not performed because of the danger of resputtering the metallic material throughout the chamber. However, as the amount of organic residues on substrates increases, the need to perform plasma cleaning processes concurrently increases, leading to an increase in processing chamber downtime due to the need to replace process kit components before the kit components have completed their expected life-cycle.
Therefore, there is a need for a plasma cleaning process that removes organic residues from chamber components while increasing chamber uptime.